.. under construction ..

Life on Mars

Speculations on possible life on Mars (and other planets) go back to the first days when the nature of planets as Earth-like bodies was recognized. Mars in particular was, and is still, considered as the most earth-like of all planets, as it shows polar caps, an atmosphere with meteorological activity over a stony surface, a comparable rotation period (length of day), seasonal variations, and a temperature not too different from that of Earth, compared to every other planet of our solar system. These facts were realized slowly during the 17th and 18th centruy, when Christian Huygens identified the first surface feature (Syrtis Major) in 1659 and the Polar Cap in 1672, J.D. Cassini determined the rotational period in 1666, G.F. Maraldi found in 1719 that Mars' appearance (especially the polar caps) was changing from opposition to opposition, and eventually William Herschel in 1781 and 1784 made the first maps of Mars and found that "its inhabitants" would probably "enjoy" conditions similar to that on Earth in many respects.

19th century observers became convinced to see dark lakes and oceans between bright continents on Mars, andthat the seasonal changes could be best understood as melting of ice in summer, and freezing again in winter season.

In 1877, Giovanni Schiaparelli observed a network of lines covering the planet's whole surface, which he called "canali", the Italian word for either channels or canals. We know now that this was a product of a combination of moderate overall observing conditions (those features were on the limit of observability), where the human eye sometimes tends to connect spots to lines. While Schiaparelli thought more of natural features, others, and above all, Percival Lowell got more and more convinced of an artificial nature of these features, constructed by some sort of advanced civilization on Mars. Lowell was wealthy enough to build a major observatory which at that time was primarily devoted to study these features on Mars, and published his observations in a number of publications, including his 1895 book "Mars" which is now available online.

Speculation on life (including "intelligent" Martians) continued through the decades. Some scientists, among them Svante Arrhenius from Sweden, argued early that Mars would be a cold and probably hostile environment, but others speculated that the seasonal changes could be vegetation effects like those observed on Earth.

These views survived well until the first spacecraft, Mariner 4, arrived at Mars and transmitted its famous photographs, showing a moonlike cratered terrain without any signs of considerable vegetation, and measured atmosphere and temperatures much less comfortable for most creatures on Earth, although some experiments indicated that some primitive forms of Earth life could perhaps survive Martian conditions at least for some time. After Mariner 4, Mariner 6 and 7 flew by Mars and determined that its atmosphere was mainly made up of Carbon Dioxide. At this time, 1970, Mars looked as lifeless and even life hostile as never considered before, and probably never later.

The first Mars orbiter, Mariner 9, revived some hope for all those considering life on Mars. Mariner 9 cartographed virtually the whole planet and found a diversity of interesting landforms, including high volcanoes, huge canyons, extended chaotic terrain and dry river beds indicating the former presence of huge quantities of water on ancient young planet Mars.

The Viking spacecraft of 1975-76 had biochemical laboratories on board, allowing for the search for life in 3 experiments. These experiments provided, at last, interesting but inconclusive results: There must be some reactive matter at least in some of the probes investigated, but most scientists concluded that this would probably be non-biological. However, in 1997, Viking Life experimentator Gilbert V. Levin claimed that his experiments may have detected evidence for active microbial life on Mars.

On August 6, 1996, scientist of Nasa and Stanford University announced the discovery of possible evidence for the existence of fossil life on Mars, found in meteorites of probable Martian origin, recovered in Antarctica.

The successfully landed Mars Pathfinder and its small robotic rover Sojourner discovered evidence for large water abundances on ancient Mars in July 1997, thus supporting the possibilities of ancient life on the Red Planet. Among the first results of the orbital survey undertaken by the Mars Global Surveyor orbiter spacecraft was a confirmation of this evidence.

The two spacecraft which should do further research of Mars within the Mars Surveyor 1998 project and in particular, the possibility of finding life on the planet, Mars Climate Orbiter and Mars Polar Lander, unfortunately failed. So it is left to the orbiter 2001 Mars Odyssey and new spacecraft like Nasa's 2003 Mars Exploration Rovers and ESA's Mars Express to bring more light in this most interesting field of research.

Comments, corrections, and propositions to this page are welcome ! Contact me !

Hartmut Frommert [contact]

[Mars] | [Spider] @ [SEDS]

Last Modification: February 28, 1998